Refractory wall construction



May 27, 1941. HENZEL ETAL 2,243,339

REFRACTORY WALL CONSTRUCTION Filed June 10. 1959 2 Sheets-Sheet 1 INVENTORS .TOHN H- HENZEL EDMUND 7T HEINRICH XTTORNEYS v Patented May 27,1941 OFFICE,

REFRACTORY WALL CONSTRUCTION John H. Henzel and Edmund-'1. Heinrich, i

Cleveland, Ohio Application June 10, 1939, Serial No. 278,511

13 Claims.

This invention relates to wall structures and more particularly to animproved refracto y and/or insulating wall especially adapted for use infuel burning furnaces or the like.

In the building of walls which will withstandthe high temperaturesencountered in modern furnace practice numerousattempts have been madeto provide for the expansion and contraction which necessarily occurs inthe wall structure during furnace operation. Bricks of refractorymaterial have been supported on various crating at temperatures whichwould otherwise necessitate special heat resisting alloy; the provisionof a. wall structure having a refractory intypes of metallic wallmembers. In numerous cases these bricks have been of special form withresulting greatly increased expense'over the cost of standardrectangular 'bricks. Furthermore, the metal supports for the refractorymaterial have previously been partly embedded in the useful or mainportion of the refractory thereby pot only shortening the life or periodof usefulness of the refractory, due to decreased thickness ofrefractory between its hot face and its metal support, but alsonecessitating the use of special alloy metal to resist and withstand thehigh temperatures due to the proximity of the metal sup.- port to thehot face of the refractory. Another important consideration is the heatloss factor, which increases in direct ratio to the temperature of themetal supporting the refractory as, regardless of design, the metalserves to drain the heat from the refractory and any reduction intemperature of the refractory supporting system or any part thereofincreases the efficiency of the wall from a thermal storage viewpoint.It is also frequently desirable to build into the wall structureinsulating material in order to retain and prevent waste of heat byradiation from the furnace walls. In order properly to retain theinsulating material in position wires or other special fastening meanshave been employed.

It is among the objects of our present invenner surface supported bysimple and effective means, which supporting means may also locate andhold in position insulating material; the provision of a refractory wallin which expansion and-contraction of the refractory material does notexert forces which are carried into the furnace shell or casing, thuspermitting the use of an'extremely light casing with resulting saving inweight,'material and installation; the provision of a wall structurewhich makes possible the utilization of a relatively large percentage ofthe refractory material as refractory, rather than merely reinforcementof refractory to make possible its suspension from metal arms orsupporting members; the provision of a wall structure which makesefllcient use of dead or non-circulating air, confined in relativelysmall cells, to take the place of costly special shaped refractorypreviously used; and the provision of an insulating refractory wallwhich is simple and economical to install and maintain, which is verytion to provide a refractory wall structure the supporting elements ofwhich may be largely fabricated in the shop and easily installed byrelatively unskilled workmen on the job and which is adapted to employ alarge percentage of standard minimum cost 9" refractory bricks with arelatively small number of one other type brick which is essentially astandard large brick with a slot of very simple form and which may bemade by slotting a standard large brick, on the job if desired. Otherobjects of our invention are the provision of refractory wall supportingmeans having hangers which are subjected to so little of the heat fromthe furnace that they may be made of cast iron for application tofurnaces opefficient and which provides a minimum metal path from theinner portion of the wall to the outer portion thereof thussubstantiallyreducing the heat loss therethrough.

The above and other objects of our invention will appear from thefollowing description of several embodiments thereof, reference beinghad to the accompanying drawings, in which Figure l is a fragmentaryperspective view of a refractory wall embodying one form of ourinvention.

Figure 2 is a fragmentary perspective view of a corner arrangement ofthe same type of wall as shown in Figure 1.

Figure 3 is a plan view of one of the refractory brick and insulationsupporting brackets employed in the wall structure of Figures 1 and 2.

Figure 4 is an end elevation of the bracket shown in Figure 3.

Figure 5 is a perspective view generally similar to Figure 1 butillustrating a slightly modified form of our wall structure.

Figure 6 is a view of the refractory supporting bracket used inthe wallof Figure .5.

Figure '7 is an end elevation of the bracket shown in Figure 6.

Referring particularly to Figure 1, our improved wall structure, in apreferred form, includes a plurality of spaced vertically extendingbrick-stays or columns I.

The shell or casing 1 units, generally indicated at C, are arranged insuperimposed relation extending between the vertical columns I. Theseunits C comprise casing plates 2, which are riveted or otherwisesuitably secured to the columns I, and which have.

abutting flanged horizontal edges 3 which are bolted or rivetedtogether, as seen at 4. Inwardly projecting vertical ribs 5 are securedto the plates 2, preferably by welding, and are provided with spacedholes 5. These holes lie in horizontal rows and accommodate the bolts 1which fasten the brackets B to the ribs 5 and which in turn support theload carrying courses of refractory bricks I8 and the sheets ofinsulating material 8. The ribs 5 stiffen the plates 2 and make possiblethe use of light weight casing members without sacrifice of strength.

As is clearly seen in Figures 1, 3 and 4, the brackets B each have avertical flange 9 through which a bolt I extends, clamping the bracketagainst the side of a rib 5. The brackets are preferably castings and,as will be later explained, may be made of ordinary cast iron. The ribor flange 9 connects to the vertical back portion III which hasangularly extending brick engaging flanges II and I2. The base portion I3 is connected to both the flanges I I and I2 and the back I and hasoutwardly projecting legs I4 and I5 which carry the vertically extendinginsulation retaining flanges I6 and I1.

The insulation 8 is made in panels of suitable material which are equalin width to the distance between adjacent vertical ribs 5, of a heightequal to the distance between the base portions I3 of adjacentvertically spaced brackets B, and a thickness equal substantially to thedistance between the outer face of the back III and the inner face ofthe flanges I6 and I I of the brackets B. Each of these insulatingpanels 8 is supported and held in position by engagement, at each of itscorners, with one of the brackets B. 'As the flanges I6 and H are spacedfrom the plates 2, when the panels of insulation are placed in position,an air space is formed between the inner surface of the plates 2 and theouter surface of the insulating panels 8. It will be seen that, as theseair spaces are continuous and free from obstructions from furnacefoundation to roof or arch, they may be utilized as natural stacks toinduce vertical air currents between casing and insulation to cool theinsulation and therelv insure a low casing temperature with comparativeabsence of temperature stresses. In other cases it may be desirable thatthese spaces be used as ducts to convey air from a fan or blower to thefurnace for combustion air requirements, thereby gain ing all theadvantages of a low casing temperature plus the increased furnaceeillciency to be gained by the use of preheated air for combustion. Instill other instances the spaces may be sealed top and bottom withdividers or headers at intermediate points thereby confining the air toform dead air spaces as additional insulation. The fan connections andthe dividers or headers just referred to are not shown in theaccompanying drawings but may be of any suitable type.

As noted above, the brackets B are secured to the ribs 5 by means ofbolts I which extend through the holes 6. This results in the bracketsbeing arranged in vertically spaced horizontal rows.

Each row of brackets B supports one of the load carrying courses ofrefractory bricks I8. These bricks are preferably standard 9" largebrick (9" x 6%" x 2 with the center to center distance between adjacentribs 5 being approximately equal to twice the length of one of thebricks. All of the supporting courses of bricks I8 are identical andeach brick I8 is provided with a slot or groove I9, located adjacent oneend and which may conveniently be sawed into the refractory brick afterit is made. These slots I9, as illustrated, are preferably cut at anangle to the ends of the bricks and fit-over the angle webs II and I2 ofthe brackets B. A preferred design of bracket B, as illustrated inFigures 3, 4, 6 and 7, is one in which the longitudinal dimension of thehorizontally extending base I 3 a is such that the base will extend toor past the center of each supported brick in the lengthwise direction,thereby restricting the tendency of the bricks to rotate about theiraxes. The unslotted or free end surface 20 of each of the bricks I8abuts the. corresponding free end of the adjacent brick I8 while theslotted end of each brick I8 abuts the slotted end of the next adjacentbrick which is supported by the same bracket B. Of course, suitablecement or plaster is used between the brick ends. Due to this abuttingrelation of the ends of the bricks I8, and due to the engagement of theflanges or webs' II and I! of the brackets B with the slots in thebricks I8, and

' because of the engagement of a portion of the vertical outeredge ofeach brick I8 with the vertical back III of the brackets B, the bricksof each load supporting course are firmly supported and prevented fromcollapse although they may expand or contract in any direction withoutimposing serious strains on either the bricks or the supporting wallstructure.

As shown in Figure 1, each course of load carrying bricks I8 supportsthree courses of relatively narrow wall bricks 2|. These three coursesof wall bricks 2I are laid in the usual overlapping fashion. on top ofeach load carrying course of bricks I8 and the inner faces of all of thebricks are aligned to provide a plane refractory surface. Cement is usedbetween the brick surfaces in the usual manner. Although the supportedwall bricks 2| substantially fill the space between the load carryingcourses of the wall, each section of the wall, comprising a loadcarrying course and three supported courses laid on top thereof,constitutes an independent self supporting unit and may be removed orreplaced without effecting the rest of the wall structure. In some caseswhere strength is not such an important consideration the load carryingcourses may be spaced vertically at greater intervals. Actual tests haveshown that one load carrying course, without any support below, willsuccessfully carry as many as 25 to 30 courses of supporting bricks. Inthe walls shown in Figures 1 and 5 only 25% of the total number ofbricks making up the wall engage and are supported by the bracketmembers. Of course, if more than three courses of intermediate or wallbricks 2| are carried by each load carrying course the percentage ofbricks which are supported by brackets will be further reduced. Forexample, if nine courses of bricks 2| were supported by a single courseof load carrying bricks I8 only 10% of the total number of bricks in thewall would be other than standard 9" bricks laid up in the usualfashion. Even if only two courses of standard bricks are carried by eachload carrying course still only one-third of the total number of bricksare in contact with the supporting bricks.

Inspection of Figure 1 will show that additional air spaces are createdbetween the outer edges of the bricks 2| and the inner surfaces of theinsulating panels 8. These air spaces are dead and run horizontally ofthe wall structure but extend vertically only between two' adjacentcourses of load carrying bricks I! as these had carrying bricks extendto and substantially engage the surfaces of the insulating panels 8. Itwill also be noted that a large portion, on the -order of one-third thetotal horizontal surfaces,

of the supporting or load carrying bricks l8 and a large percentage ofthe highest temperature portions of the brackets B are exposed to theair in these spaces or cells. Considering this in connection with thelaw of physics which states that the volume of heat transferred througha medium or from one medium to another is a function of the differencein temperature, the greater the diiference the greater the volume ofheat transferred, it will be seen that a considerable volume of heatwill be transferred from the bricks l8 and brackets B to the air withinthe cells by a combination of radiation and convection. While thetemperature of the air within the cells is raised by this action thedifference in thetemperature within the cells is, compared toatmospheric'temperature, too slight to cause an appreciable loss of heatthrough the insulation panels 8 to atmosphere. The increase of thetemperature of the air within the cells lowers the temperaturediflerential between the hot and cold faces of the bricks 2| therebyreducing the heat transfer or loss through the portion of the wallformed by the bricks 2|; and the heat lost from the brackets B to theair within the cells lowers the temperature differential between the hotand cold ends of the brackets thereby reducing what might otherwise be aconsiderable heat loss due to conduction through the insulation 8 bymeans of the metal of the brackets B. The creation of these dead airspaces therefore greatly increases the efliciency of the wall structureand effectively prevents heat losses in undesirable quantities.

Another of the important features of our invention is achieved by thesmall size of the bracket members B and the small area of contactbetween these brackets and the load supporting courses of the refractorybrick structure. By reducing the area of contact between the brick andmetal parts of the wall the transfer of heat from the bricks to thecasing is further reduced. As a metal path forms an excellent means forconducting heat to the outer surface of the wall from whence it may belost to the atmosphere, it is evident that our wall structure, whichuses a relatively small number of brackets engaging with small contactarea only a relatively few of the bricks which make up the wall, resultsin reducing to a minimum the heat loss by conduction through metalpaths. All of our metal castings B are so protected from the heat of thefurnace, due to the fact that the intermediate or wall bricks 2| stopshort of the inner edges of the brackets B and due to the small contactbetween the brackets and the load carrying bricks l8, that we have foundthat we are able successfully to use cast iron brackets for furnacetemperatures which in all types of prior structures of this type withwhich we are familiar have necessitated expensive heat resisting alloyor the members in direct contact with the bricks.

Cast iron has a safe working temperature of approximately 650 F. andwhen this temperature is exceded cast iron disintegrates due toexcessive grain growth and may permit the entire wall structure tocollapse. with our furnace wall structure we have found that the ture atthe outermost portions of the brackets B does not exceed 450 F. even inhigh temperature furnaces where the temperature adjacent the inner faceof the refractory bricks may be as high as 1850 F.

The wall illustrated in Figures 1 and 2 includes a supporting bracket22, havinga flange 23 extending through the brick work to a suitable web24 to which it is bolted or otherwise secured. The web 24, asillustrated, is secured to the vertical stud or column I. Tubes 25, foroil cracking or other purposes, are supported in the tion 8 in Figurenotches in the brackets 22 and it will be understood that in other typesof wall structures these tubes and their supporting brackets may besupported by other means or entirely omitted. The arrangement ofrefractory bricks and theirsupports is, of course, equally well adaptedfor use in various other kinds of furnaces such as arr-- nealing,baking, normalizing, etc.

, In Figure 2 we have illustrated a corner construction embodying thefeatures of the wall structure shown in Figure 1. Each of the adjoiningwalls D and E are built up as illustrated in Figure 1. Where the wallsmeet, the bricks IQ of each load carrying course overlap. This is madepossible by locating each horizontal row of brackets B of the wall Dabove the corresponding rows of brackets B of the wall E a distanceequal to the thickness of a single brick. The casing members 0 of theadjoining walls extend to and are supported by the columns 26 and 21. Bymeans of the staggered or offset location of the load supporting coursesand the generally indicated at F and which is shown in enlarged detailin Figures 6 and '7. These brackets F each have a vertical web 28provided with spaced holes 29 and 30 which accommodate bolts Si by whichthe brackets are secured to the webs 5. These webs are somewhat narrowerthan the webs 5 of Figure 1 and, as the brackets F are not provided withoutwardly extending portions H or l5 or with the insulation retainingflanges l6 and ll of the brackets B, the insula- 5 is disposed betweenthe casing sheets 2 and the outer surfaces of the back portions 32 ofthe brackets F. In the wall of Figure 5 no air space is provided betweenthe casing sheets 2 and the insulating panels 8. The load carryingbricks l8 engage and are supported by the angular flanges 33 and 34 andrest upon the base 35 of the brackets F in the same manner asillustrated in Figure 1. v

The same construction as is shown in Figure 5 may be used with theomission of,.the insulation 8 where heat'losses are of no consequence,or the space occupied by the insulation can be utilized to provide airducts to preheat air for combustion where it is desirable to obtain agreater preheat temperature than is possible with an insulated wall.

The intermediate, supported bricks 2| in Figure 5 are spaced from theinsulation 8 a distance equal to the depth of the base portion 35 of.the

brackets F and thus it will be observed that the temperawall of Figure'fi permits a most eflicient use of the standard rectangular refractorybricks in the same manner as the structure of Figure 1. A minimum .ofbrick surface is in contact with the metal supports. The size and weightof l the metal supports is reduced to a practical minimum and, by ampleprotection of the brackets B and F from the heat of the furnace, plussufficient heat drainage from the brackets, their failure due toexcessive heat is completely eliminated even though the brackets B and Fare made of ordinary cast iron.

In our improved wall structure only one relatively small and lightweight type of brick supporting bracket is employed. These brackets maybe used interchangeably and if a furnace is dismantled the old bracketsmay be used without alteration in another furnace. Our constructionpermits the prefabrication of the casing sheets 2 with the ribs 5drilled and attached to locate properly the brick supporting brackets Bor F. It is only necessary for the erector on the job to mount thepanels 2 on suitable vertical supports, attach the brackets B or F bybolting them to the ribs 5, and then start building up the brickstructure, with or without the insulating panels 8 as may be desired. Ifitis necessary to repair or replace any part of the wall structure theintermediate supported wall bricks 2| can be removed between any twoadjacent load carrying courses of bricks it without disturbing the restof the structure as each load carrying course carries only its owncourses of standard bricks. Corners can readily be constructed becausethe bricks of the load carrying courses of one wall have cantileversupports on their brackets and extend out into overlapping relation withthe bricks of the corresponding load carrying courses of the other wall.

Although we have described the illustrated embodiments of our inventionin considerable detail it will be understood by those skilled in the artthat variations and modifications may be made without departing from thescope of our invention and we do not, therefore, wish to be limited tothe particular arrangements herein shown and described, but claim as ourinvention all embodiments thereof coming within the scope of theappended claims.

We claim:

1. In a wall structure of the type described, the combination of acasing having a plurality of spaced vertical ribs extending inwardlytherefrom, a plurality of brick supporting brackets secured to said ribsand arranged in vertically spaced horizontal rows, courses of loadsupporting bricks supported by each of said rows of brackets, andintermediate courses of bricks, narrower than said load supportingbricks, substantially filling the spaces between said load supportingcourses.

2. In a wall structure of the type described, the combination of acasing, a plurality of inwardly projecting vertically extending ribmembers secured to said casing, brick supporting brackets secured tosaid ribs and arranged in a horizontal row, a course of bricks supportedby said row of brackets, each bracket of the row being adapted tosupport, in abutting relation, the ends of two adjacent load carryingbricks the opposite free ends of which engage the free ends of otherload carrying bricks similarly supported by adjacent brackets, and acourse of supported bricks carried by said course of load carryingbricks.

- and each bracket supporting brackets, each of 3. In a wall structureof the type described, a plurality of brick supporting brackets, meansfor supporting said brackets in a horizontal row, a course of loadcarrying bricks supported by said brackets, each of said bricks beingsupported at one end by a bracket and engaging an adjacent brick at itsother or free end, the length of said bricks being equal toapproximately one-half the horizontal center to center distance betweenbrackets and each bracket supporting the ends of two bricks. 4

4. In a wall structure of the type described, a plurality of bricksupporting brackets, means for supporting said brackets in a horizontalrow, a course of load carrying bricks supported by said said bricksbeing supported at one end by a bracket and engaging an adjacent brickat its other or free end, the length of said bricks being equal toapproximately one-half the horizontal center to center distance betweenbrackets and each bracket supporting the ends of two bricks, saidbrackets having brick engaging flanges and brick supporting bases andsaid bricks being slotted to fit said flanges.

5. In a wall of the type described, a plurality of brick supportingbrackets, means for supporting said brackets in a horizontal row, acourse of load carrying bricks supported by said brackets, each of saidbricks being supported at one end by a bracket and engaging an adjacentbrick at its other end, the length of said bricks being equal toapproximately one-half the horizontal center to center distance betweenbrackets the ends of two bricks, and a course of supporting bricks,narrouer than said load carrying bricks, disposed on said course of loadcarrying bricks with their inner faces aligned with the inner faces ofsaid load carrying bricks.

6. In a wall of the type described, a casing, a plurality of bricksupporting brackets secured to said casing, a plurality of loadsupporting bricks, each of said load supporting bricks being supportedon a bracket, said load supporting bricks being arranged in verticallyspaced horizontal courses with the bricks of each course in end to endabutting relation, courses of wall bricks substantially filling thespaces between said courses of load supporting bricks, said wall bricksbeing narrower than said load supporting bricks, and panels of heatinsulating material supported by said brackets and disposed between theouter surfaces of said load carrying bricks and said casing.

7. A brick supporting bracket for wall structures comprising a verticalflange portion adapted to be secured to a supporting member, a baseportion attached to said flange and disposed horizontally, a backportion extending substantially at right angles to said flange and baseportions, and a pair of spaced brick engaging flanges extendingvertically upwardly from said base portion and arranged one on each sideof said vertical flange portion.

8. A brick supporting bracket for wall structures comprising a. verticalflange portion adapted to be secured to a supporting member, a baseportion attached to said flange and disposed horizontally, a backportion extending substantially at right angles to said flange and baseportions, and a pair of brick engaging flanges extending verticallyupwardly from said base portion and angularly disposed relative to theplane of said brick portion at the same but opposite angle-E wherebysaid brick engaging flanges diverge away from said back portion.

9. A brick supporting bracket for wall structures comprising a verticalflange portion adapted to be secured to a supporting member, a baseportion attached to said flange and disposed horizontally, a backportion extending substantially at right angles to said flange and baseportions, a pair of brick engaging flanges extending vertically upwardlyfrom said base portion, and leg portions extending from said baseportion adjacent each end thereof, said leg portions having insulationretaining means at their ends.

10. A brick supporting bracket for wall structures comprising a verticalflange portion adapted to be secured to a supporting member, a baseportion attached to said flange and disposed horizontally, a backportion extending substantially at right angles to said flange and baseportions, a pair of brick engaging flanges extending vertically upwardlyfrom said base portion and angularly disposed relative to the plane ofsaid back portion at the same but opposite angles whereby said brickengaging flanges diverge away from said back portion, and leg portionsextending from said base portion adjacent each end thereof, said legportions having insulation retaining means at their ends.

11. A brick supporting bracket for wall structures comprising a flangeportion adapted to be secured to a supporting member, a base portionattached to said flange and disposed horizontally, a back portionextending substantially at right angles to said flange and baseportions, and brick-holding means adapted to engage and hold bricks inend to end relation on said base portion.

12. A brick supporting bracket for wall structures comprising a flangeportion adapted to be secured to a supporting member, a base portionattached to said flange and disposed horizontally, a back portionextending substantially at right angles to said flanges and baseportion, and brick-holding means adapted to engage and hold a brick onsaid base portion against movement longitudinally or transverselythereof.

13. In a wall of the type described, a plurality of brick supportingbrackets, means for supporting said brackets in spaced relation inhorizontal rows, each of said brackets including a base portion having asubstantially horizontally extending brick supporting surface andbrick-holding means adapted to engage and hold a brick on said baseagainst substantial movement longitudinally or transversely thereof, aplurality of load supporting bricks, each of said load supporting brickshaving smooth top and bottom surfaces and being supported on a bracketand held in position by said maintaining means, said load supportingbricks being arranged in vertically spaced horizontal courses, andcourses of wall bricks substantially filling the spaces between saidcourses of load supporting bricks.

JOHN H. HENZEL. EDMUND T. HEINRICH.

